Investments, Forward Contracts and Fair Value Measurements - Measured at Fair Value (Details) - USD ($) $ in Millions	Dec. 29, 2018	Jun. 30, 2018
Debt available-for-sale securities
Total debt available-for-sale securities	$ 29.1	$ 189.6
Money market funds	226.8	354.9
Trading securities	1.5	1.6
Foreign currency forward contract (1)	1.0	2.7
Total assets	258.4	548.8
Liability:
Foreign currency forward contract (3)	5.6	11.7
Contingent consideration	36.2	0.0
Total liabilities	41.8	11.7
Prepayments and other current assets
Debt available-for-sale securities
Total assets	1.0
Other current assets
Debt available-for-sale securities
Total assets		2.7
Cash and cash equivalents
Debt available-for-sale securities
Total assets	215.8	364.8
Short-term investments
Debt available-for-sale securities
Total assets	30.0	169.3
Restricted cash
Debt available-for-sale securities
Total assets	7.1	7.3
Other non-current assets
Debt available-for-sale securities
Total assets	4.5	4.7
Other current liabilities
Liability:
Total liabilities	5.6	11.7
U.S. treasuries
Debt available-for-sale securities
Total debt available-for-sale securities	4.0	35.9
Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	3.5	13.2
Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	1.7	2.7
Asset-backed securities
Debt available-for-sale securities
Total debt available-for-sale securities	4.0	23.5
Corporate securities
Debt available-for-sale securities
Total debt available-for-sale securities	15.9	114.3
Level 1
Debt available-for-sale securities
Total debt available-for-sale securities	4.0	35.9
Money market funds	226.8	354.9
Trading securities	1.5	1.6
Foreign currency forward contract (1)	0.0	0.0
Total assets	232.3	392.4
Liability:
Foreign currency forward contract (3)	0.0	0.0
Contingent consideration	0.0	0.0
Total liabilities	0.0	0.0
Level 1 \| U.S. treasuries
Debt available-for-sale securities
Total debt available-for-sale securities	4.0	35.9
Level 1 \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 1 \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 1 \| Asset-backed securities
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 1 \| Corporate securities
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 2
Debt available-for-sale securities
Total debt available-for-sale securities	25.1	153.7
Money market funds	0.0	0.0
Trading securities	0.0	0.0
Foreign currency forward contract (1)	1.0	2.7
Total assets	26.1	156.4
Liability:
Foreign currency forward contract (3)	5.6	11.7
Contingent consideration	0.0	0.0
Total liabilities	5.6	11.7
Level 2 \| U.S. treasuries
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 2 \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	3.5	13.2
Level 2 \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	1.7	2.7
Level 2 \| Asset-backed securities
Debt available-for-sale securities
Total debt available-for-sale securities	4.0	23.5
Level 2 \| Corporate securities
Debt available-for-sale securities
Total debt available-for-sale securities	15.9	114.3
Level 3 Investments
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Money market funds	0.0	0.0
Trading securities	0.0	0.0
Foreign currency forward contract (1)	0.0	0.0
Total assets	0.0	0.0
Liability:
Foreign currency forward contract (3)	0.0	0.0
Contingent consideration	36.2	0.0
Total liabilities	36.2	0.0
Level 3 Investments \| U.S. treasuries
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 3 Investments \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 3 Investments \| Municipal bonds and sovereign debt instruments
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 3 Investments \| Asset-backed securities
Debt available-for-sale securities
Total debt available-for-sale securities	0.0	0.0
Level 3 Investments \| Corporate securities
Debt available-for-sale securities
Total debt available-for-sale securities	$ 0.0	$ 0.0

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Fair value of financial and nonfinancial obligations.

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